The Blockheads, Water Rats, London

A fan barely moves the warm, soupy air inside the packed pub back room. It’s the sort of place where Ian Dury played with his band Kilburn and the High Roads in the early 1970s, one leg ravaged by polio, his Essex guttersnipe wit and intransigent attitude influencing a watching Johnny Rotten. But it was his next band the Blockheads who provided the jazz-funk, pub-rock engine which powered his greatest work, often co-written with Chaz Jankel.

Since Dury’s death from cancer in 2000, last year’s biopic with Andy Serkis, Sex & Drugs & Rock & Roll, and Paul Sirett’s great theatre musical Reasons to be Cheerful, have revived his work. The decision of the Blockheads to carry on, though, provides the purest connection.

Making two more albums to date, they’re a focal point for the mostly middle-aged fans here tonight. Dury’s former roadie and minder Derek the Draw is at the mic: Dury’s retainer, not his replacement. Impassive behind green bottle-top Lennon specs, handlebar moustache white, he’s a conduit for the parts of his boss’s spirit he shares. The band start with two of his co-writes with Jankel for Staring Down the Barrel (2009), “George the Human Pigeon” and “A Little Knowledge”. “Before I could shake a stick at a jack-rabbit...” Derek muses in the pub tale preceding the latter, dry cockney wit, wordplay and voice just right. Dury’s furious charisma isn’t sought.

Mick Gallagher’s jazzy piano introduces “Inbetweenies”, Dury’s happily salacious lyric (“put your fingers where my mouth just went...”) preceding the better-known “Wake Up And Make Love With Me”. Norman Watt-Roy pulls the trigger on its finish with a pluck of his bass. A revered player, knees and elbows always at sharp, hip angles, he and Israeli jazz saxophonist Gilad Atzmon are the musicians to watch.

Many of the crowd choose discretion over valour in the sweaty back room, resting at the bar till a favourite song starts. Mine is “Sweet Gene Vincent”, a tribute to the late, gammy-legged rocker with poetry and power which is now one to Dury. “Hit Me With Your Rhythm Stick” gains thuggish force from the fans, jazzy subtleties abandoned to dance and let rip. This strange afterlife for a band who’ve lost their leader wouldn’t work for everyone. The Attractions without Elvis Costello? But the Blockheads keep something no one else can do breathing.